Brace lock



2 Sheets-Sheet l A. c. BORGMAN oct. 1, 1963 BRACE LOCK Filed Nov. 13, 1961 Oct. 1, 1963 A. c. BORGMAN BRACE LOCK 2 sheets-sheen` 2 Filed Nov. 13, 1961 United States Patent O 3,105,710 BRACE LOCK Arthur C. Bergman, Franklin Square, N.Y., assigner to The Patent Scaifolding Co., Inc., Long Island City,

' Filed Nov.13,1961,ser.No.151,622

z claims. (C1. 287-58) This invention relates to an improved telescoping brace for collapsible scaffolding.

Movable scaoldng which can be collapsed or vfolded for ready transportation and compact storage has been the subject of a great deal of engineering and invention and in consequence is already highly developed. Nevertheless, a very effective and greatly improved novel tolding mobile scaffold is described and claimed in the copending application of Nesslinger and Borgman, Serial No. 108,232, led May 4, 1961. This scaffold-ing involved to provision of a plurality of side members or braces formed of telescoping tubes pivotally fastened at their intersection. In this structure great compactness, ease of erection, and stiiness and ultimate strength when erected was achieved. To prevent collapse of the telescoping -braces when fully extended provision was made for locking them in that position. A locking rod of smaller diameter than the smaller of the two telescoping tubes was provided with an externally accessible actuating lever and an internal locking pin `or bolt, the latter engaging with shoulders or lugs providing a keeper on one of the telescop-ing tubes. When the brace 'was fully extended the projecting end of the actuating lever was moved through a small arc so that the locking pin on the rod engaged with said shoulders or lugs and locked the two tubes in their extended position. A spring detent was provided to prevent accidental unlocking .by turning said lever. The device worked perfectly except for carelessness on the part of a workman erecting the scaffolding who might fail to turn the lever, rod and locking pin to locking position.

Accordingly, an object of my present invention is to afford `protection against the possibility of such human error while retaining all of the advantages of the telescoping braces of the Nesslinger and Borgman application above referred to. Essentially, the present invention provides for automatic locking when the brace tubes are fully extended without the need 4for conscious attention to the locking device. Means are provided for turning the locking rod with its locking pin by the act of extension, the lever projecting through the outer telescoping tube being held in its end positions by a spring detent so that the reverse operation cannot take place until this lever has been deliberately moved to unlocking position. The construction is no more complicated than the aforesaid manually locked telescoping brace even though it aiords the additional advantage in operation of automatic locking.

A preferred construction will be described in conjunction with the drawings in which:

FIGURE 1 is an isometric view of a telescoping brace adapted for use with scaiold structures of the type referred to in said prior application. K

FIGURE 2 -is a detail view partly in elevation and partly in central longitudinal section and partly broken away, of the locking parts of the brace in unlocked condition.

FIGURE 3 is a view similar -to FIGURE 2, but with sections taken on an axial plane perpendicular to that of FIGURE 2, and with the locking rod and connected parts rotated to locked position.

FIGURES 4, 5 and 6 are cross-sections taken on lines 4 4, 5 5, and 6 6 respectively of FIGURE 2.

FIGURES 7 and 8 are isometric views partly in trans- 3',lll5,7l0 Patented Oct. 1, 1963 ICC verse section of a fragment of the brace broken olf just to the right of the lock actuating lever as seen in FIGS. 2 and 3, i.e. in locked and unlocked positions respectively.

FIGURE 9 is an isometric view in longitudinal section of the twisting cam block for rotating the locking rod and connected parts.

The telescoping brace to the extent that it includes a larger tube ilA and a smaller tube 2 and end fastenings 3 and 4 is the same essentially as in the Nesslinger and Borgman device. =A tubular locking rod 8 is rotatably mounted coaxially in said tubes with the outer end of a rod actuating lever 10 projecting ,through a slot`6. An internal lock-ing p-in or bolt carried by rod 8, instead of being turned into engagement with keepers in the form of lugs or projections moves, as in the application aforesaid and is arranged with its ends slidably engaged in opposite spiral grooves 7 in a sleeve member 5 shown in FIGURES 2, 3 and 9.

The outer end of rod 8 is journaled in a bearing in the outer end of the larger telescoping tube and is held therein .against endwise movement by lever 10 riding in slot 6 normal to the axis of the tube. Lever 10 advantageously projects through slot 6 suiiiciently beyond tube 1 so ythat it can be manually pushed along the slot.

In operation, with the tube 2 fully or partly telescoped into tube 1 and the lever 10 pulled to the end of slot 6 as 'seen in FIGURE 2, the telescoped or partly telescoped tubes are freely extensible until the locking pin 9 enters the open ends of grooves 7. This it does readily because it is held in proper alignment with said groove ends by lever 10 being held by spring detent 11 in the unlocked posi-tion shown in FIG. 2. The corner-s at such open ends of the grooves may be cut back, as at 7a, to facilitate further such entry of the locking pin 9. Further extension of the brace tubes results in camming the locking pin 9 around the spiral grooves 7 and consequently, rotating the rod 8 in -its bearings until the lever 10 reaches the hump of spring 11. IIf suiicient force is exerted in extending the brace parts, or the extension is sufficiently rapid to provide momentum, the resisting force of spring 11 may be overcome suciently to permitlever 10 to depress and pass over the hump and thus to latch on itsy opposite side abutted against the end of slot 6 as seen in FIG. 3. Otherwise, it may be necessary to manually push the projecting portion of lever 10 circumferentially until itis latched over the hump of spring 11. This locks the brace tubes against relative endwise movements because the lever '10 cannotmove back in the slot to unlocking position unless the hump on the spring is pushed out of the way.

When the brace is .to be telescoped again to its shorter length, the spring 11 is flexed to depress the hump out of the Way of lever 10, or the projecting end of lever 10 is pushed with sutiicient force along slot 6 to cam the spring down and move past the hump toward its lock releasing position, FIG. 2. Once the lever 10 is thus released from restraint by the hump of detent spring 11, the tubes 1 and 2 can be telescoped together by direct endwise push as therod 8 is free to turn in relation to sleeve 5 and does so, and the pin 10 slides along the arcuate slot 6 to its unlocking position as seen in FIG. 2. When the locking pin 9 reaches the ends of grooves 7, the lever is back in its initial unlocking position where it is releasably retained by spring 11 in position to align pin 9 with the ends of grooves 7. Thus in telescoping the tubes together the pin 9 moves out beyond the ends of the grooves 7 and still will reenter the grooves when the tubes are again moved toward extended condition.

It should be noted that while the rod 8 is free to turn 10' and the friction of pin 9 in :the spiral groove 7 are such that the locking pin 9 cannot be forced through the sleeve until the detent has been deliberately unlocked by the workman. This is due in part :to the shape of the spring presenting an easier slope to locking than to unlocking.

On extension of the brace, the lever 10 can automatically lock and thereafter has the necessary rigidity for its Vsaid structure, said inner tube having secured at its inner end a sleeve coaxial with said tubes and provided with a central bore and opposed spirally arranged grooves opening inwardly into said bore and `opening through the outer end of said sleeve into said inner tube, and said sleeve having an end wall extending across and closing the inner ends of said grooves, a locking rod mounted coaxially and rotatably in said larger tube and in said bore of the sleeve, a locking pin on said rod having end portions extending radially therefrom, and into positions to be engaged by said end wall of the sleevewhen said tubes are in extended condition, an actuating and positioning lever on said rod having its outer end extending radially therefrom through said yarcuate slot to retain said rod against longitudinal displacement in the brace and being angularly movable in said slot between its ends to rotate said rod and said pin into and out of their end positions in relation to said sleeve, a spring detent arranged in the path of said angular movement of said lever in said slot to releasably retain said lever and said locking pin in said end positions, said locking pin being arranged and adapted to be slidably engaged by said grooves in the sleeve :to rotate said rod during portions of extending and telescoping relative endwise movements of said tubes andl to be in disengaged relation -to said grooves during other portions of said relative endwise movements of the tubes,

and said locking pin being arranged and adapted, when' engaged by said end wall of lthe sleeve, to arrest relative extending movement between said tubes, and said lever and detent when the lever is in one of said end positions being arranged and adapted in cooperation with said rod to releasably lock the locking pin in position at the closed ends of said grooves adjacent 4to said end wall ofthe sleeve, and when the lever is in the other of its end positions to yieldingly retain said rod and pin in position to be re-engaged by the open ends of said grooves while the latter are in said disengaged relation to said locking pin when the tubes are again moved toward extended condition.

2. In a brace for foldable scaiolds the combination of an outer tube having an arcuate eircumferentially directed slot and an inner tube telescoping therewith, means for limiting relative extending movement between said :tubes and for releasably locking the same against relative telescoping movement when they are -in extended condition, said means including a locking rod mounted coaxially and rotatably in the brace but held against'longitudi-- nal displacement therein, said rod having a radiallydirected arcuating lever extending :through said slot and a` i rotate said rod on its longitudinal axis when force is applied to eiect differential endwise movement between said tubes, and a yielding keeper operatively positioned on said outer tube in the path of angular movement of said lever in said slot and arranged and adapted to releasably retain said lever in an end position in said slot and said locking rod in locking position when said tubes are in fully extended relation.

References Cited in the le of this patent UNITED STATES PATENTS 2,267,802 Purdy Dec. 30, 1941 

2. IN A BRACE FOR FOLDABLE SCAFFOLDS THE COMBINATION OF AN OUTER TUBE HAVING AN ARCUATE CIRCUMFERENTIALLY DIRECTED SLOT AND AN INNER TUBE TELESCOPING THEREWITH, MEANS FOR LIMITING RELATIVE EXTENDING MOVEMENT BETWEEN SAID TUBES AND FOR RELEASABLY LOCKING THE SAME AGAINST RELATIVE TELESCOPING MOVEMENT WHEN THEY ARE IN EXTENT CONDITION, SAID MEANS INCLUDING A LOCKING ROD MOUNTED COAXIALLY AND ROTATABLY IN THE BRACE BUT HELD AGAINST LONGITUDINAL DISPLACEMENT THEREIN, SAID ROD HAVING A RADIALLY DIRECTED ARCUATING LEVER EXTENDING THROUGH SAID SLOT AND A TRANSVERSELY DISPOSED BOLT, AND TORQUE IMPARTING MEANS CARRIED BY SAID INNER TUBE AND OPERATIVELY ENGAGING SAID BOLT TO IMPART ANGULAR MOVEMENT THERETO AND THEREBY TO ROTATE SAID ROD ON ITS LONGITUDINAL AXIS WHEN FORCE IS APPLIED TO EFFECT DIFFERENTIAL ENDWISE MOVEMENT BETWEEN SAID TUBES, AND A YIELDING KEEPER OPERATIVELY POSITIONED ON SAID OUTER TUBE IN THE PATH OF ANGULAR MOVEMENT OF SAID LEVER IN SAID SLOT AND ARRANGED AND ADAPTED TO RELEASABLY RETAIN SAID LEVER IN AN END POSITION IN SAID SLOT AND SAID LOCKING ROD IN LOCKING POSITION WHEN SAID TUBES ARE IN FULLY EXTENDED RELATION. 